Perry Sanders Jr. is ready to have Katherine Jackson sign paperwork to be reinstated as guardian of Michael's three children ... Paris, Prince and Blanket, however we've learned exclusively that TJ Jackson has instructed security to not allow him into Katherine's Calababas home.

Our Jackson family source tells X17online exclusively:

"TJ won't allow Perry to do his job and won't allow his grandmother to speak to any of her children. Trent and the security team, who Katherine fired already, are refusing to leave the premises. They also won't answer the phone at the house. Family members are worried sick about Katherine's safety. Once again, they are using trickery. "

Just yesterday, Tito Jackson's 34-year-old son was granted temporary guardianship. However, as X17 first reported, Katherine's attorney Perry Sanders Jr. is ready to file paperwork "asap."

We told you first that Katherine fired Trent and the entire security team before leaving her vacation spot in Arizona to come home. Our family source, who heard the phone conversation, says Katherine directly told Trent, "You better be gone by the time I return home." Trent replied with the following: "We don't work for you, we work for the estate. We're not leaving."

The Jacksons tell us they believe family advisor John Branca was behind the confrontation on Monday at the Jackson estate between Janet, Randy, Jermaine, Paris, Prince, Trent and the security team.

Following Monday night's altercation at the Jackson compound in Calabasas, Branca and the estate's co-executor John McClain, released the following statement:

"We are concerned that we do what we can to protect them from undue influences, bullying, greed, and other unfortunate circumstances. While we do not have standing to directly intervene, we have monitored the situation and will continue to do so. We believe measures are being put in place that will help protect them from what they are having to deal with."

Family members tell us they believe Branca "is trying to paint a picture that under Katherine's supervision, the kids aren't being cared for" and that "TJ is being coached" by Branca.

UPDATE: 6:30 PM PST - The Jackson family has confirmed to us that Katherine is safe at this moment, despite TJ blocking her attorney from entering the home.

UPDATE: 9:40 PM PST - Perry Sanders Jr., Mrs. Jackson's attorney, was eventually allowed into the home to speak with Katherine. Sanders tells X17: "I had a long and productive meeting today with Mrs. Jackson. I am pleased to report that she is fine and she laughed at the widely publicized report that she had suffered a stroke. I will be releasing a formal statement tomorrow morning regarding the results of the meeting."